The present invention relates to an apparatus for producing a water mist, i.e., atomized water particles of a fog-like nature. The apparatus is especially designed for low manufacturing cost and low operating cost.
Evaporative coolers and humidifiers have long been used to generate and distribute humidified air for such purposes as air conditioning and plant watering. In most cases, the apparatus involves the use of electric motors for pumping the air or atomizing the water, and operating costs are relatively high. The present invention contemplates a water-atomizing device which operates without electric motors or similar power devices. In one form of the invention, a nozzle structure has an elongated rotary pin rotatably arranged in a nozzle passage. Small angulated flow ducts are defined in the downstream end of the pin so that flow of pressurized water through the ducts imparts a rotary force to the pin. The pin rotates on its axis at a relatively high rotational rate, e.g., in excess of two thousand revolutions per minute.
These miniature flow ducts are arranged to discharge small jets of water into an expansion chamber defined between the downstream end of the rotating pin and an exit opening or hole in the nozzle structure. Flow through each duct is so restricted that the water is atomized into a multiplicity of very small particles as it passes from a highly pressurized liquid condition at the inlet end of the duct to essentially atmospheric pressure at the outlet end of the duct. The rapid rotation of the pin causes each stream of water particles to have a spiralling motion as it exits the exit opening in the nozzle.
The spiral motions of the water particles generate centrifugal forces which disperse the water particles radially relative to the nozzle axis. The water particles are thus diffused over a relatively wide volume.
A plurality of nozzles having rotary pin atomizers therein may be spaced along a water header pipe to provide a fog or mist curtain. With the pipe disposed in an overhead location relative to a room or human habitation space, such as an outdoor patio or swimming pool deck, it is possible to lower the local space temperature by as much as thirty degrees. The cost of operation of the system is relatively low, because the system relies solely on the water supply pressure to perform the water-atomizing function.